The present invention relates generally to semiconductor devices utilizing optical interconnects, and more particularly, to improving coupling efficiency between such devices.
As semiconductor devices process larger amounts of information, higher communication speeds between such devices are desirable. In order to address this desire, silicon photonics, an optical communication technology in which data is transferred among computer chips by optical rays, has been increasingly developed.
Traditional microchips (ICs or chips) utilize electrical interconnections between embedded devices and other chips to process and move data. Silicon photonic chips utilize optical interconnects to allow communication to occur between devices and chips through the propagation of light. Optical, or light, coupling refers to a method of interconnecting two devices to transfer an optical signal using light waves, and is often accomplished through the use of a coupling device or coupler. Optical coupling devices are often made up of a planer waveguide and a diffractive grating coupler (DGC) formed on a silicon-on-insulator (SOI) device and a second planer waveguide. Such waveguides may be used as multimode waveguides; however, single mode waveguides may be preferable due to the relative quality of communication and attenuation of light propagating in the waveguide.